Add shsEnum and shrEnum

2 files changed, 14 insertions, 0 deletions

diff --git a/src/Data/Array/Nested/Ranked/Shape.hs b/src/Data/Array/Nested/Ranked/Shape.hs
index 488b4d8..a1fa247 100644
--- a/src/Data/Array/Nested/Ranked/Shape.hs
+++ b/src/Data/Array/Nested/Ranked/Shape.hs
@@ -330,6 +330,13 @@ shrZipWith f (ShR l1) (ShR l2) = ShR $ listrZipWith f l1 l2
 shrPermutePrefix :: forall n i. [Int] -> ShR n i -> ShR n i
 shrPermutePrefix = coerce (listrPermutePrefix @i)
 
+shrEnum :: IShR sh -> [IIxR sh]
+shrEnum = \sh -> go sh id []
+  where
+    go :: IShR sh -> (IIxR sh -> a) -> [a] -> [a]
+    go ZSR f = (f ZIR :)
+    go (n :$: sh) f = foldr (.) id [go sh (f . (i :.:)) | i <- [0 .. n - 1]]
+
 
 -- | Untyped: length is checked at runtime.
 instance KnownNat n => IsList (ListR n i) where
diff --git a/src/Data/Array/Nested/Shaped/Shape.hs b/src/Data/Array/Nested/Shaped/Shape.hs
index 10e1a9d..6eaec10 100644
--- a/src/Data/Array/Nested/Shaped/Shape.hs
+++ b/src/Data/Array/Nested/Shaped/Shape.hs
@@ -389,6 +389,13 @@ shsFromListS (_ ::$ l) = SNat :$$ shsFromListS l
 shsFromIxS :: IxS sh i -> ShS sh
 shsFromIxS (IxS l) = shsFromListS l
 
+shsEnum :: ShS sh -> [IIxS sh]
+shsEnum = \sh -> go sh id []
+  where
+    go :: ShS sh -> (IIxS sh -> a) -> [a] -> [a]
+    go ZSS f = (f ZIS :)
+    go (n :$$ sh) f = foldr (.) id [go sh (f . (i :.$)) | i <- [0 .. fromSNat' n - 1]]
+
 
 -- | Untyped: length is checked at runtime.
 instance KnownShS sh => IsList (ListS sh (Const i)) where